1. Field of the Invention
The present invention relates to a power output apparatus and an automobile. More specifically the invention pertains to a power output apparatus that is capable of outputting the power from an internal combustion engine and the power from a driving motor to a drive shaft, as well as to an automobile that is driven with the power from the internal combustion engine and the power from the driving motor, which are output to the drive shaft linked with an axle.
2. Description of the Prior Art
A proposed power output apparatus disconnects a generator, which uses the power of an output shaft of an internal combustion engine to generate electric power, in the process of starting the internal combustion engine (for example, JAPANESE UTILITY MODEL LAID-OPEN GAZETTE No. 4-79942). This power output apparatus separates the generator from the output shaft of the internal combustion engine at the time of starting the internal combustion engine, thereby reducing the load applied to the internal combustion engine at the start thereof and improving the starting ability of the internal combustion engine.
The technique of disconnecting the generator from the internal combustion engine at the starting time is applicable to a start of the internal combustion engine in the driving state of a motor in a power output apparatus where the power from the internal combustion engine and the power from the motor are output to a drive shaft. The prior art technique, however, does not take into account the effects of the motor in the driving state on the start of the internal combustion engine. In a hybrid vehicle with such a power output apparatus mounted thereon, the start of the internal combustion engine in the course of a drive with the motor is an important issue to specify the drivable range with the motor.
The object of the present invention is thus to extend a drivable range with a motor in a power output apparatus that outputs the power from an internal combustion engine and the power from the motor to a drive shaft as well as in an automobile that is driven with the power output from the internal combustion engine and the power from the motor to the drive shaft. The object of the invention is also to attain a smooth start of the internal combustion engine in the power output apparatus and the automobile.
In order to achieve at least a part of the aforementioned objects, the power output apparatus and the automobile of the present invention are structured as follows.
The power output apparatus of the present invention is capable of outputting power from an internal combustion engine and power from a driving motor to a drive shaft, the power output apparatus including: a secondary battery that supplies electric power to the driving motor; a starting module that starts the internal combustion engine with a supply of electric power from the secondary battery; and a control module that drives and controls the driving motor to output a required power in a preset range of driving electric power to the drive shaft while the internal combustion engine is at a stop, where the range of driving electric power is set as a difference between a maximum electric power output from the secondary battery and a starting electric power required by the starting module to start the internal combustion engine.
The power output apparatus of the present invention drives and controls the driving motor to output a required power in a preset range of driving electric power to the drive shaft while the internal combustion engine is at a stop. Here the range of driving electric power is set as a difference between a maximum electric power output from the secondary battery and a starting electric power required by the starting module to start the internal combustion engine. This arrangement enables the internal combustion engine to be started immediately in response to a starting requirement of the internal combustion engine, and effectively prevents the power output from the driving motor from being varied in the course of starting the internal combustion engine.
As one aspect of the power output apparatus in the present invention further including: at least one auxiliary machinery that is driven with a supply of electric power from said secondary battery; wherein said control module drives and controls said at least one auxiliary machinery to stop its operation until completion of a start of said internal combustion engine, while controlling said starting module to start said internal combustion engine, in response to a starting requirement of said internal combustion engine that is at a stop. In this case, the power output apparatus stops the operations of the auxiliary machinery at the time of starting the internal combustion engine. This arrangement desirably heightens the level of the driving electric power used for the driving motor by the electric power required for driving the auxiliary machinery and thereby extends the drivable range with the driving motor, compared with the prior art structure of controlling the driving motor in a differential range obtained as subtraction of the electric power required for driving the auxiliary machinery and the electric power required for starting the internal combustion engine from the maximum electric power output from the secondary battery.
As another aspect of the power output apparatus in the present invention, the control module may control the starting module to start the internal combustion engine in a continuous driving state of the at least one auxiliary machinery, in response to the starting requirement of the internal combustion engine, when the driving motor is driven and controlled to output the required power to the drive shaft in a specific range of electric power calculated by subtracting electric power required for actuation of the at least one auxiliary machinery from the driving electric power. Further, the control module may set the starting electric power in such a manner as to be lowered with an increase in revolving speed of the drive shaft, calculate the driving electric power from the setting of the starting electric power to drive and control the driving motor with the calculated driving electric power, and control the starting module to start the internal combustion engine with the setting of the starting electric power.
As another aspect, the power output apparatus of the present invention further including: a three-shaft power input and output module that has a first shaft linked with an output shaft of the internal combustion engine, a second shaft linked with the drive shaft, and a third shaft, where power input into and output from a residual one shaft among the three shafts is determined according to powers input into and output from any two shafts among the three shafts, wherein the starting module may include a starting motor that is linked with the third shaft and is capable of generating electric power, and the driving motor may be linked with the drive shaft.
The technique of the present invention is not restricted to the power output apparatus discussed above, but may be applicable to a moving body, such as an automobile. The power output apparatus and the automobile are only examples of application of the invention. The principle of the invention is also attained by a control method.